UNION MORAINE. 493 



to be no theoretical objection to the view that the segments of the esker 

 were fornred in succession from south to north, the southern end of each 

 segment terminating at the ice margin, but the phenomena, so far as 

 interpreted, do not bear clear evidence on this point. The inner chain of 

 raorainic ridges, along Campbells Creek, may have been formed before the 

 completion of the esker, and it seems not improbable that the portion of 

 the esker on the north side of the Mississinawa, if not all that lies north of 

 sec. 18, T. 21, R. 11 E., is to be connected with this later ice margin. 



The trough in which this esker lies consists of a broad, shallow channel 

 leading from the Mississinawa Valley near Granville south-southwest to 

 White River at Muncie, ranging in width from one-fourth mile or less up 

 to fully 1 mile, and excavated to a depth of 10 to 25 feet below the level 

 of the bordering till plains. A less sharply outlined valley leads from 

 Muncie southward to the main morainic system. This valley is bordered 

 on the west, throughout the greater part of its length, and on the east for a 

 less distance, by low drift knolls and ridges which stand slightly above the 

 bordering plains. This distribution indicates that they were probably 

 produced in connection with the formation of the esker. 



It is not certain that the excavation of the trough is restricted to the 

 time during which the Union moraine was formed. The fact that it 

 connects on the south with a similar channel that leads out to the main 

 morainic system lends support to the view that the excavation began before 

 the ice sheet withdrew from that morainic system. It seems probable, 

 however, that a subglacial stream continued to occupy the northern end 

 until the Union moraine was formed. There are in eastern Indiana other 

 channels similar to the one under discussion, which have their southern ends 

 in the main morainic system and extend back within the limits of later 

 moraines. They strongly suggest a close succession in the development 

 of moraines, with but little shifting in the course or position of subglacial 

 streams. The other channels fall within the limits of the East White River 

 lobe and will be discussed in a report covering that lobe. A short channel 

 of this class, crossing the Union moraine just west of Selma, has attracted 

 considerable attention because of the difficulties of constructing a railway 

 across it.^ This channel leads to White River and apparently finds con- 

 tinuation in a channel of similar character that extends southward from 



'See Eleventh Ann. Kept. Geol. Survey Indiana, 1881, pp. 130-131; also Fifteenth Ann. Kept., 

 p. 104. 



